In manufacturing small-size electronic components, it is often necessary to make connection between different modules of electronic parts making up a completed device. In view of the large number of electrical connections generally required, the industry has made such connections between modules with a flexible flat multi-conductor cable, commonly called ribbon wire, or with a flexible flat printed circuit board having parallel conductors in the form of thin paths of copper on a flexible substrate.
A common prior art method of attaching the conductors of a ribbon wire to a standard printed circuit board consists in the steps of inserting the conductors of the ribbon wire into their assigned holes, and soldering the wire ends either by hand or by dipping the board and wire ends into a solder tank. In pratice, this rather conventional method of connecting wires to a printed circuit board presents extreme difficulties when attempting to use such a method for ribbon wire. In particular, it is extremely difficult to ensure that all of the conductors are properly seated in their respective holes in the printed circuit board during the soldering operation. Since the ribbon wire is very lightweight and very flexible, an operator has difficulty in maintaining accurate holding forces on the cable, and an occasional wire is left unsoldered without the operator's knowledge.
Since the soldering operation of the ribbon wire onto a circuit board is done by the assembly line method, and since the flexible ribbon wire is light in weight and often very short, after the printed circuit board is conveyed to the circuit tank and the conductors of one end of the ribbon wire are inserted into the holes of the board and all of the wires have been properly seated, a proper soldering procedure can, with difficulty, be accomplished. However, in order to connect the other end of the ribbon wire to another printed circuit board by the solder tank method, the printed circuit board having the conductors of the ribbon wire already connected to the board has to be properly positioned so as to prevent the already connected terminals from becoming unsoldered and allowing the ribbon wire to slip out of the holes while being conveyed into the solder tank. In order to ensure then that one end of the ribbon wire will not come loose when the other end is being soldered, the conveyor equipment for the automatic solder tank operation must be more complicated in its structure leading to either prohibitive expense or impracticability. For this reason, manufacturers have resorted to individual soldering by hand as the conventional method for attaching ribbon wires to printed circuit boards. This procedure is, of course, cumbersome, time consuming and costly.
In order to avoid the problems associated with solder tank techniques, an attempt has been made to eliminate the need for soldering by affixing the female part of a connector onto a printed circuit board and making connection to the points on the printed circuit board that require connection to another location in the apparatus. Attempts were then made to insert and thus connect the ends of a ribbon wire or flexible printed circuit board to the contacts of the female connector. However, due to the thin and flexible nature of the ribbon wire or flexible printed circuit board strips, reliable connection to the female connector has proven to be impossible. Additional attempts have been made to lower the contacting pressure of the female contact in order to permit insertion of the ribbon wire or flexible printed circuit board, but this has led to additional problems. Added to the low reliability of contact, any small outside force can interrupt such a connection easily, or vibrating the apparatus may cause temporary disconnection, etc.